This invention relates generally to devices and methods for delivering an agent, such as a hemostatic agent, to a body lumen or cavity.
The prostate is a gland in the male urinary system located directly below the bladder and surrounding the urethra. A common urological disorder that some men encounter is enlargement of the prostate due to disease or decreases in hormone production. Generally, the enlarged prostate tends to constrict the urethra resulting in reduced urination flow and/or urine retention.
A medical professional has a number of options to treat a patient suffering from retention caused by the enlargement of the patient""s prostate. One option is to perform a surgical procedure that cuts or removes parts of the patient""s diseased prostatic tissue (the enlarged section of the prostate). Another option is to insert a device, such as, for example, a stent to facilitate drainage of urine and/or blood from the patient""s bladder and urethra.
The invention involves controlling bleeding associated with the insertion of medical devices (such as stents) and/or surgical procedures that involve cutting of tissue. The present invention generally relates to stents that are able to deliver a hemostatic agent during or after the insertion of the stent. By preventing bleeding in the tissues surrounding the stent, obstruction or other problems that can occur when the blood coagulates inside or around the stent are reduced or avoided.
In one aspect, the invention relates to a prostatic stent. The prostatic stent is used to maintain an open passageway from a patient""s bladder through the urethra and to deliver an agent to tissue within the patient""s urinary system. The prostatic stent includes a first segment, a second segment, a connecting segment, and the agent. The first and second segments can be tubular members disposed on either side of the patient""s external sphincter and connected together by the connecting segment. The first segment includes an external surface coated with the agent, an internal surface, a distal end, a proximal portion, and a lumen defined by the internal surface and extending within the first segment. (The directional terms distal and proximal require a point of reference. Herein, the reference point in determining direction is in the perspective of the patient. Therefore, the term distal herein refers to a direction that points out of the patient""s body, and the term proximal refers to the direction that points into the patient""s body.) The proximal portion includes at least one opening in communication with the lumen for draining fluid from the patient""s bladder. The second segment includes an external surface, an internal surface, a distal end, a proximal end, and a lumen defined by the internal surface and extending within the second segment. The connecting segment is a thin flexible member adapted to extend through an opening within the patient""s external sphincter without interfering with the normal function of the external sphincter. When the prostatic stent is placed with the patient""s body, the first segment is located on the proximal side of the patient""s external sphincter, the second segment is located on the distal side of the patient""s external sphincter, and the connecting segment extends between the first and second segment within the external sphincter.
Embodiments of this aspect of the invention can include the following features. The agent on the external surface of the first segment may be a hemostatic agent that controls or stops bleeding within a tissue. The hemostatic agent may be in the form of a powder, a liquid, a gel, or a fibrous matrix embedded within a biodegradable polymer. The external surface of the second segment may also be coated with the hemostatic agent. The internal surfaces of the first and second segments may be coated with an anticoagulant agent that prevents blood from coagulating and thus occluding the lumens of the first and second segments. The prostatic stent may further include a suture or other thin flexible member attached to the distal end of the second segment. The suture should be long enough to extend from the distal end of the second segment through the patient""s urethra and terminate in close proximity to the meatus.
In general, in another aspect, the invention relates to a method of placing the prostatic stent within a patient""s urinary system. A medical professional inserts and positions the prostatic stent with the aid of a stylet. The stylet includes a proximal end and a distal end and is sized to fit within the lumens of the first and second segments of the prostatic stent. Prior to inserting the prostatic stent, the medical professional passes the stylet through the lumens of the second and first segments, thereby removably connecting the prostatic stent to the stylet. The medical professional then inserts and advances the prostatic stent until the proximal portion of the first segment is located within the bladder of the patient. When properly positioned, the first segment of the prostatic stent is located on the proximal side of the external sphincter, the second segment is located on the distal side of the external sphincter, and the connecting segment extends through the external sphincter. Once the prostatic stent is properly positioned, the medical professional removes the stylet from the prostatic stent and from the patient""s urethra, thereby leaving the prostatic stent to remain positioned within the patient""s urinary system. The agent, which is on the external surface of the first segment, is transferred to the tissue of the urethra during insertion and after placement of the prostatic stent. The prostatic stent may be removed from the patient""s body at some later time by simply pulling on the suture or through endoscopic means.
In general, in another aspect, the invention relates to a prostatic stent that includes ports adapted to delivering an agent to the prostatic stent. The prostatic stent includes a first segment, a second segment, and a connecting segment. The first and second segments are tubular members disposed on either side of the patient""s external sphincter and are connected together by the connecting segment. The first segment includes an external surface, an internal surface, a distal end, a proximal portion, a lumen defined by the internal surface and extending within the first segment, and a plurality of ports for conveying the agent to the external surface of the first segment. The proximal portion includes at least one opening in communication with the lumen for draining fluid from the patient""s bladder. The second segment includes an external surface, an internal surface, a distal end, a proximal end, and a lumen defined by the internal surface and extending within the second segment. The connecting segment is a thin flexible member adapted to extend through an opening within the patient""s external sphincter without interfering with the normal function of the external sphincter. When the prostatic stent is placed within a patient""s body, the first segment is located on the proximal side of the patient""s external sphincter, the second segment is located on the distal side of the patient""s external sphincter, and the connecting segment extends between the first and second segment within the external sphincter.
Embodiments of this aspect of the invention can include the following features. The internal surfaces of the first and second segments may be coated with an anticoagulant agent that prevents blood from coagulating and thus occluding the lumens of the first and second segments. The second segment may include a plurality of ports for conveying the agent to the external surface of the second segment. The prostatic stent may further include a suture or other thin flexible member attached to the distal end of the second segment. The suture should be long enough to extend from the distal end of the second segment through the patient""s urethra and terminate in close proximity to the meatus.
The agent to be delivered to the prostatic stent may be a hemostatic agent or other drug, and may be in the form of a liquid, gel, or powder. The agent may also be formed from a two component formulation such as, for example, combining a polymerizing agent with a polymerizable agent. In some embodiments, the agent is discharged to the prostatic stent during insertion to treat the entire urethra. In other embodiments, treatment is concentrated to a specific region of the patient""s urethra and therefore, the agent is discharged after placement of the prostatic stent within the patient""s prostatic urethra.
In general, in another aspect, the invention relates to a method of placing the prostatic stent within a patient""s urinary system and delivering an agent to the prostatic stent in vivo. A medical professional inserts and positions the prostatic stent with the aid of a stylet. The stylet includes a proximal end, a distal end, a fluid channel for conveying the agent, and a plurality of openings in fluid communication with the fluid channel. The stylet is sized to fit within the lumens of the first and second segments of the prostatic stent, and the plurality of openings on the stylet are sized and positioned to communicate with the plurality of ports within the first segment of the prostatic stent when the stylet and stent are connected. Prior to inserting the prostatic stent, the medical professional passes the stylet through the lumens of the second and first segments and aligns the plurality of openings on the stylet with the plurality of ports on the prostatic stent, thereby creating a continuous pathway for a fluid to flow. Connected to the distal end of the stent is a syringe containing the active agent that is to be delivered to the stent. The medical professional then inserts and advances the prostatic stent and stylet until the proximal portion of the first segment is located within the bladder of the patient. The medical professional may either activate the syringe resulting in the discharge of the agent to the prostatic stent either during insertion or after the prostatic stent has been properly positioned. When properly positioned, the first segment of the prostatic stent is located on the proximal side of the external sphincter, the second segment is located on the distal side of the external sphincter, and the connecting segment extends through the external sphincter. Once the prostatic stent is properly positioned and the agent has been discharged to the prostatic stent, the medical professional removes the stylet from the prostatic stent and from the patient""s urethra, thereby leaving the prostatic stent to remain positioned within the patient""s urinary system. The prostatic stent may be removed from the patient""s body at some later time by simply pulling on the suture or through endoscopic means.
In some embodiments, the stylet may feature a first fluid channel, a second fluid channel, and a fluid mixing channel to accommodate an agent that is formed from a polymerizing agent and a polymerizable agent. The medical professional simultaneously discharges the polymerizing agent into the first fluid channel and the polymerizable agent into the second fluid channel. The polymerizing and polymerizable agents mix together forming the agent in the fluid mixing channel and the agent is then delivered to the plurality of ports in the first segment of the prostatic stent.
The foregoing and other objects, aspects, features, and advantages of the invention will become more apparent from the following description and from the claims.